Scraper Bottom Discharge Centrifuge for MVR Crystallized Salt Dewatering

The Scraper Bottom Discharge Centrifuge is designed for dewatering crystallized salt slurry discharged from MVR evaporation and crystallization systems.

In an MVR salt recovery process, water is removed through mechanical vapor recompression until the dissolved salt reaches supersaturation and crystals form. The resulting crystal slurry contains salt crystals, concentrated mother liquor, dissolved impurities, and residual process liquid. The centrifuge separates the crystals from the mother liquor, supports optional cake washing, reduces residual moisture, and automatically discharges the dewatered salt cake through the bottom outlet.

This equipment is particularly suitable for MVR systems where the upstream evaporation and crystallization section operates steadily while the downstream solid-liquid separation section works in automatic batches. An agitated slurry buffer tank is normally used between the MVR crystallizer and centrifuge to stabilize feed concentration and match crystallizer output with centrifuge cycle time.

Peony provides the solid-liquid separation section between MVR crystallization and downstream salt handling.

MVR Crystallizer → Agitated Slurry Buffer Tank → Scraper Bottom Discharge Centrifuge → Mother Liquor Recycle / Purge → Salt Drying / Screening / Packaging

The MVR crystallizer operates continuously, while the centrifuge works in automatic batches. An agitated slurry buffer tank connects the two sections, stabilizes crystal concentration, prevents settling, and supplies slurry to the centrifuge at a controlled rate.

Inside the centrifuge, mother liquor is separated from the crystal cake and collected for recycle, evaporation, or controlled purge. Optional cake washing can reduce residual mother liquor before drying. The scraper then removes the dewatered salt cake automatically through the bottom outlet.

Solution Focus

• Stable MVR-to-centrifuge connection through buffered and controlled slurry feeding
• Mother liquor recovery for recycle, concentration, or impurity purge
• Lower dryer load through centrifugal dewatering before salt drying
• Controlled cake washing to improve salt cleanliness while limiting salt loss
• Automatic bottom discharge for reliable transfer to downstream drying and packaging

The final configuration is selected based on crystal size, slurry solids concentration, mother liquor viscosity, recycle route, salt washing requirement, target moisture, and corrosion conditions.

The crystallized salt slurry is withdrawn from the MVR crystallizer or slurry buffer tank and fed into the rotating basket lined with filter media.

1. Controlled Crystal Slurry Feeding
   Crystallized salt slurry is fed into the rotating basket at a controlled rate. The feed sequence is adjusted according to slurry solids concentration and basket loading capacity.
2. Mother Liquor Filtration
   Concentrated mother liquor passes through the filter medium and is collected through the filtrate outlet.
3. Salt Cake Formation
   Salt crystals remain inside the basket and gradually form a filter cake on the basket wall.
4. Optional Cake Washing
   Process-compatible wash liquid can be introduced to reduce residual mother liquor and improve salt cleanliness. The wash method should be selected carefully to avoid excessive salt dissolution or unnecessary disturbance to the MVR water balance.
5. Spin Drying
   The basket continues rotating at high speed to reduce free mother liquor retained in the salt cake.
6. Automatic Scraping
   After the programmed dewatering cycle, the scraper removes the salt cake from the basket wall.
7. Bottom Discharge
   The dewatered salt is discharged through the bottom outlet and transferred to downstream drying, screening, storage, packaging, reuse, or further treatment.

The complete cycle is automatically controlled through PLC operation to maintain stable batch dewatering and consistent coordination with the upstream MVR crystallization process.

Material selection should be based on actual mother liquor chemistry, chloride concentration, sulfate content, pH, temperature, dissolved oxygen, cleaning chemicals, and corrosion history.